Anisotropically conductive moisture barrier films and electro-optic assemblies containing the same

ABSTRACT

An electro-optic assembly includes a layer of electro-optic material configured to switch optical states upon application of an electric field and an anisotropically conductive layer having one or more moisture-resistive polymers and a conductive material, the moisture-resistive polymer having a WVTR less than 5 g/(m2*d).

REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.16/716,618, filed Dec. 17, 2019, which claims priority to U.S.Provisional Application No. 62/780,401 filed on Dec. 17, 2018. Allpatents and publications disclosed herein are incorporated by reference.

BACKGROUND OF INVENTION

This invention relates to anisotropically conductive films that may beincorporated in electro-optic assemblies. More specifically, in oneaspect this invention relates to anisotropically conductive films thathave improved moisture barrier properties that may be incorporated intoelectro-optic devices or displays.

The term “electro-optic”, as applied to a material or a display, is usedherein in its conventional meaning in the imaging art to refer to amaterial having first and second display states differing in at leastone optical property, the material being changed from its first to itssecond display state by application of an electric field to thematerial. Although the optical property is typically color perceptibleto the human eye, it may be another optical property, such as opticaltransmission, reflectance, luminescence or, in the case of displaysintended for machine reading, pseudo-color in the sense of a change inreflectance of electromagnetic wavelengths outside the visible range.

Anisotropically-conductive adhesives have been used in the assembly ofmicroelectronics for many years. As exemplified in U.S. Pat. No.4,729,809, a typical approach involves loading a thermally-curable epoxyresin with electrically-conductive particles at slightly below thepercolation threshold of conductivity. This formulation is then appliedbetween a semiconductor chip and a circuit board with correspondingelectrical contacts. Under heat and pressure, the conductive particlesare trapped between the contacts of the chip and board to complete theconnection without causing shorting due to lateral conductivity.

In addition to the sub-percolation threshold approach, variousapproaches to orient the conductive particles with either an electric ormagnetic field have been used to form anisotropically-conductive filmsand adhesives. These include use of conductive fibers (U.S. Pat. No.4,170,677), magnetic particles such as iron oxide (U.S. Pat. No.7,843,626), and carbon black oriented in an electric field (U.S. Pat.No. 9,437,347)

Another approach at providing anisotropically conductive films isdisclosed in U.S. Patent Application No. 2017/0052421, whichincorporates the conductive film in a direct-write system utilizingpositive and negative corona sources to write or erase, respectively,black and white electrophoretic film. This produces a display that canbe addressed in a non-contact manner without the need for any drivingelectronics on the display device. A thick, anisotropically-conductivelayer is provided as a protective layer over the electrophoreticmaterial containing microcapsules in order to prevent mechanical damageto the microcapsules. Anisotropic conductivity is required to allow theions from the coronas to pass through the protective layer to the layerof electrophoretic material. This conductivity is accomplished by addingelectrically-conductive, magnetic particles to a UV curable resinformulation. The loading of the particles is chosen so that exposure toa strong magnetic field aligns the particles in a perpendicularorientation to the plane of the protective layer so that electricalconductivity is achieved in the Z-direction, without any significantlateral conductivity in the X- or Y-directions. Once aligned, the matrixresin is cured with UV radiation to both harden the protective layer andlock in the particle orientation.

One of the main disadvantages of the anisotropically conductive layerdisclosed in U.S. Patent Application No. 2017/0052421 is the poorimaging quality at high ambient humidity. Thus, there is a need foranisotropically conductive films with improved moisture barrierproperties to preserve the image quality of the display.

SUMMARY OF THE INVENTION

According to one aspect, an electro-optic assembly comprises a layer ofelectro-optic material configured to switch optical states uponapplication of an electric field and an anisotropically conductive layercomprising one or more moisture-resistive polymers and a conductivematerial, the moisture-resistive polymer having a WVTR less than 5g/(m²*d).

These and other aspects of the various embodiments of the presentinvention will be apparent in view of the following description.

BRIEF DESCRIPTION OF THE FIGURES

The drawing Figures depict implementations in accord with the presentconcepts, by way of example only, not by way of limitation. In theFigures, like reference numerals refer to the same or similar elements.

FIG. 1 is a schematic cross-sectional side view of one embodimentaccording to the present invention.

FIG. 2 is a schematic cross-sectional side view of another embodimentaccording to the present invention.

FIG. 3 is a schematic cross-sectional side view of yet anotherembodiment according to the present invention.

DETAILED DESCRIPTION

Generally, the various embodiments of the present invention provide ananisotropically conductive layer and method of forming the same that hasinherent moisture vapor barrier properties. This is accomplished byincluding a moisture resistive polymer in the continuous phase of theanisotropically conductive layer that is cured or cooled duringmanufacture of the layer. This eliminates the need for an additionalbarrier-forming step and may provide a barrier with improved mechanicalintegrity. In addition, certain embodiments of the present invention maypreclude the need for specialized radiation curing equipment andeliminate the hazards of handling radiation-curable monomers.

A schematic of a preferred assembly is illustrated in FIGS. 1 and 2 ,and a process for making the assembly according to various embodimentsof the present invention is provided below. The assembly comprises asubstrate, a conductive layer, an electro-optic layer and an anisotropicconductive layer. The assembly may then be incorporated into anelectro-optic device, such as a display. An electro-optic displaynormally comprises a layer of electro-optic material and at least twoother layers disposed on opposed sides of the electro-optic material,one of these two layers being an electrode layer. In most such displaysboth the layers are electrode layers, and one or both of the electrodelayers are patterned to define the pixels of the display. For example,one electrode layer may be patterned into elongate row electrodes andthe other into elongate column electrodes running at right angles to therow electrodes, the pixels being defined by the intersections of the rowand column electrodes. Alternatively, and more commonly, one electrodelayer has the form of a single continuous electrode and the otherelectrode layer is patterned into a matrix of pixel electrodes, each ofwhich defines one pixel of the display. In another type of electro-opticdisplay, which is intended for use with a stylus, print head or similarmovable electrode separate from the display (such as the devicedisclosed in the aforementioned U.S. Patent Application No.2017/0052421), only one of the layers adjacent the electro-optic layercomprises an electrode, the layer on the opposed side of theelectro-optic layer typically being a protective layer intended toprevent the movable electrode damaging the electro-optic layer.

Embodiments of the assembly according to one embodiment of the presentinvention will now be described, though by way of illustration only,with reference to FIGS. 1 and 2 , which is a schematic section throughthe assembly The assembly (generally designated 100) shown in FIG. 1comprises a substrate 110, an electrode layer 120, an electro-opticlayer 130, and an anisotropically conductive layer 180.

In some embodiments, the substrate 110 and electrode layer 120 may belight transmissive, if the assembly 100 is to be incorporated into adisplay in which the substrate 110 is intended as the viewing side ofthe display. In other embodiments, the anisotropically conductive layer180 may be light transmissive, if it is intended to serve as the viewingsurface of a display. In yet another embodiment, all three of thelayers, substrate 110, electrode layer 120, and anisotropicallyconductive layer 180 may be light transmissive, if the assembly 100 isto be incorporated into a dual sided display. The term“light-transmissive” is used herein throughout the specification and theclaims to mean that the layer thus designated transmits sufficient lightto enable an observer, looking through that layer, to observe the changein display states of the electro-optic medium, which will normally beviewed through the electrically-conductive conductive layer and adjacentsubstrate; in cases where the electro-optic medium displays a change inreflectivity at non-visible wavelengths, the term “light-transmissive”should of course be interpreted to refer to transmission of the relevantnon-visible wavelengths.

The substrate 110 is preferably flexible, in the sense that thesubstrate can be manually wrapped around a drum (say) 10 inches (254 mm)in diameter without permanent deformation. The substrate will typicallybe a polymeric film, and will normally have a thickness in the range ofabout 1 to about 25 mil (25 to 634 μm), preferably about 2 to about 10mil (51 to 254 μm). The lower surface (in FIG. 1 ) of substrate 110,which may form the viewing surface of the final display, may have one ormore additional layers (not shown), for example a protective layer toabsorb ultra-violet radiation, barrier layers to prevent ingress ofoxygen or moisture into the final display, and anti-reflection coatingsto improve the optical properties of the display. If it is not necessaryfor the substrate 110 to be light transmissive, any compatible flexiblematerials known to those of skill in the art may be used.

Coated on to the upper surface of substrate 110 is an electricallyconductive electrode layer 120, which may serve as the common electrodein the final display device. As previously mentioned, the electrodelayer 120 may be provided in the form of a thin light-transmissive layerof metal or metal oxide, such as aluminum or ITO for example, or may bea conductive polymer. Poly(ethylene terephthalate) (PET) films coatedwith aluminum or ITO are available commercially, for example as“aluminized Mylar” (“Mylar” is a Registered Trade Mark) from E.I. duPont de Nemours & Company, Wilmington Del., and such commercialmaterials may be used with good results as the substrate 110 andelectrode 120 layers in the various embodiments of the presentinvention.

A layer of electro-optic material 130 may then be applied over theopposing surface of the electrode layer 120 relative to the substrate110. Various types of electro-optic materials may be incorporated in thevarious embodiments of the present invention, such as solidelectro-optic materials.

Some electro-optic materials are solid in the sense that the materialshave solid external surfaces, although the materials may, and often do,have internal liquid- or gas-filled spaces. Displays using solidelectro-optic materials may hereinafter for convenience be referred toas “solid electro-optic displays”. Thus, the term “solid electro-opticdisplays” includes rotating bichromal member displays, encapsulatedelectrophoretic displays, microcell electrophoretic displays andencapsulated liquid crystal displays.

The terms “bistable” and “bistability” are used herein in theirconventional meaning in the art to refer to displays comprising displayelements having first and second display states differing in at leastone optical property, and such that after any given element has beendriven, by means of an addressing pulse of finite duration, to assumeeither its first or second display state, after the addressing pulse hasterminated, that state will persist for at least several times, forexample at least four times, the minimum duration of the addressingpulse required to change the state of the display element. It is shownin U.S. Pat. No. 7,170,670 that some particle-based electrophoreticdisplays capable of gray scale are stable not only in their extremeblack and white states but also in their intermediate gray states, andthe same is true of some other types of electro-optic displays. Thistype of display is properly called “multi-stable” rather than bistable,although for convenience the term “bistable” may be used herein to coverboth bistable and multi-stable displays.

A display containing rotating bichromal member type material isdescribed, for example, in U.S. Pat. Nos. 5,808,783; 5,777,782;5,760,761; 6,054,071 6,055,091; 6,097,531; 6,128,124; 6,137,467; and6,147,791 (although this type of display is often referred to as a“rotating bichromal ball” display, the term “rotating bichromal member”is preferred as more accurate since in some of the patents mentionedabove the rotating members are not spherical). Such a display uses alarge number of small bodies (typically spherical or cylindrical) whichhave two or more sections with differing optical characteristics, and aninternal dipole. These bodies are suspended within liquid-filledvacuoles within a matrix, the vacuoles being filled with liquid so thatthe bodies are free to rotate. The appearance of the display is changedby applying an electric field thereto, thus rotating the bodies tovarious positions and varying which of the sections of the bodies isseen through a viewing surface. This type of electro-optic medium istypically bistable.

Another type of electro-optic display may use an electrochromic medium,for example an electrochromic medium in the form of a nanochromic filmcomprising an electrode formed at least in part from a semi-conductingmetal oxide and a plurality of dye molecules capable of reversible colorchange attached to the electrode; see, for example O'Regan, B., et al.,Nature 1991, 353, 737; and Wood, D., Information Display, 18(3), 24(March 2002). See also Bach, U., et al., Adv. Mater., 2002, 14(11), 845.Nanochromic films of this type are also described, for example, in U.S.Pat. Nos. 6,301,038; 6,870,657; and 6,950,220. This type of medium isalso typically bistable.

Another type of electro-optic display is an electro-wetting displaydeveloped by Philips and described in Hayes, R. A., et al., “Video-SpeedElectronic Paper Based on Electrowetting”, Nature, 425, 383-385 (2003).It is shown in U.S. Pat. No. 7,420,549 that such electro-wettingdisplays can be made bistable.

A preferred type of electro-optic material that may be incorporated inthe various embodiments of the present invention is the particle-basedelectrophoretic display, in which a plurality of charged particles movethrough a fluid under the influence of an electric field.Electrophoretic displays can have attributes of good brightness andcontrast, wide viewing angles, state bistability, and low powerconsumption when compared with liquid crystal displays.

Electrophoretic media require the presence of a fluid. In most prior artelectrophoretic media, this fluid is a liquid, but electrophoretic mediacan be produced using gaseous fluids; see, for example, Kitamura, T., etal., “Electrical toner movement for electronic paper-like display”, IDWJapan, 2001, Paper HCS1-1, and Yamaguchi, Y., et al., “Toner displayusing insulative particles charged triboelectrically”, IDW Japan, 2001,Paper AMD4-4). See also U.S. Pat. Nos. 7,321,459 and 7,236,291.

Numerous patents and applications assigned to or in the names of theMassachusetts Institute of Technology (MIT), E Ink Corporation, E InkCalifornia, LLC and related companies describe various technologies usedin encapsulated and microcell electrophoretic and other electro-opticmedia. Encapsulated electrophoretic media comprise numerous smallcapsules, each of which itself comprises an internal phase containingelectrophoretically-mobile particles in a fluid medium, and a capsulewall surrounding the internal phase. Typically, the capsules arethemselves held within a polymeric binder to form a coherent layerpositioned between two electrodes. In a microcell electrophoreticdisplay, the charged particles and the fluid are not encapsulated withinmicrocapsules but instead are retained within a plurality of cavitiesformed within a carrier medium, typically a polymeric film. Thetechnologies described in these patents and applications include:

(a) Electrophoretic particles, fluids and fluid additives; see forexample U.S. Pat. Nos. 7,002,728 and 7,679,814;

(b) Capsules, binders and encapsulation processes; see for example U.S.Pat. Nos. 6,922,276 and 7,411,719;

(c) Microcell structures, wall materials, and methods of formingmicrocells; see for example U.S. Pat. Nos. 7,072,095 and 9,279,906;

(d) Methods for filling and sealing microcells; see for example U.S.Pat. Nos. 7,144,942 and 7,715,088;

(e) Films and sub-assemblies containing electro-optic materials; see forexample U.S. Pat. Nos. 6,982,178 and 7,839,564;

(f) Backplanes, adhesive layers and other auxiliary layers and methodsused in displays; see for example U.S. Pat. Nos. 7,116,318 and7,535,624;

(g) Color formation and color adjustment; see for example U.S. Pat. Nos.7,075,502 and 7,839,564;

(h) Methods for driving displays; see for example U.S. Pat. Nos.7,012,600 and 7,453,445;

(i) Applications of displays; see for example U.S. Pat. Nos. 7,312,784and 8,009,348;

(j) Non-electrophoretic displays, as described in U.S. Pat. No.6,241,921 and U.S. Patent Application Publication No. 2015/0277160; andapplications of encapsulation and microcell technology other thandisplays; see for example U.S. Patent Application Publications Nos.2015/0005720 and 2016/0012710.

Many of the aforementioned patents and applications recognize that thewalls surrounding the discrete microcapsules in an encapsulatedelectrophoretic medium could be replaced by a continuous phase, thusproducing a so-called polymer-dispersed electrophoretic display, inwhich the electrophoretic medium comprises a plurality of discretedroplets of an electrophoretic fluid and a continuous phase of apolymeric material, and that the discrete droplets of electrophoreticfluid within such a polymer-dispersed electrophoretic display may beregarded as capsules or microcapsules even though no discrete capsulemembrane is associated with each individual droplet; see for example,the aforementioned U.S. Pat. No. 6,866,760. Accordingly, for purposes ofthe present application, such polymer-dispersed electrophoretic mediaare regarded as sub-species of encapsulated electrophoretic media.

An encapsulated electrophoretic display typically does not suffer fromthe clustering and settling failure mode of traditional electrophoreticdevices and provides further advantages, such as the ability to print orcoat the display on a wide variety of flexible and rigid substrates.(Use of the word “printing” is intended to include all forms of printingand coating, including, but without limitation: pre-metered coatingssuch as patch die coating, slot or extrusion coating, slide or cascadecoating, curtain coating; roll coating such as knife over roll coating,forward and reverse roll coating; gravure coating; dip coating; spraycoating; meniscus coating; spin coating; brush coating; air knifecoating; silk screen printing processes; electrostatic printingprocesses; thermal printing processes; ink jet printing processes;electrophoretic deposition (See U.S. Pat. No. 7,339,715); and othersimilar techniques.) Thus, the resulting display can be flexible.Further, because the display medium can be printed (using a variety ofmethods), the display itself can be made inexpensively.

Various types of electro-optic media may be used in the assemblies ofthe present invention. Referring again to the preferred embodiment ofFIG. 1 , the electro-optic layer 130 is an encapsulated electrophoreticmedium and comprises microcapsules/droplets 140, each of which comprisesnegatively charged white particles 150 and positively charged blackparticles 160 in a hydrocarbon-based fluid 165. Themicrocapsules/droplets 140 are retained within a polymeric binder 170.The electro-optic layer 130 may be deposited on the conductive electrodelayer 120, typically by slot coating, the two layers being in electricalcontact. In the alternative embodiment of FIG. 2 , an electro-opticlayer 230 may instead comprise a polymeric sheet 240 comprising aplurality of sealed microcells, and each of the sealed microcells arefilled with a dispersion of the white particles 150 and black particles160.

Upon application of an electrical field across electro-optic layer130/230, white particles 150 move to the positive electrode and blackparticles 160 move to the negative electrode, so that electro-opticlayer 130 appears, to an observer viewing the display through substrate110 and/or anisotropically conductive layer 180, white or blackdepending on whether conductive layer 120 is positive or negativerelative to an area of the anisotropically conductive layer 180.

In a first process according to an embodiment of the present invention,the anisotropically conductive layer 180 may be provided over the layerof electro-optic media 130/230 by first coating the top of the layer ofelectro-optic material 130/230 with a fluid containing a conductivematerial, one or more moisture-resistive polymers, and a plurality ofcurable monomers and/or oligomers. After coating the top surface of thelayer of electro-optic material 130/230, an electric and/or magneticfield may be applied to the fluid to cause the conductive material toalign in a direction that is generally normal to the plane of the layerof electro-optic material. In a final step, the plurality of monomersand/or oligomers are polymerized during application of the electric ormagnetic field, so that the conductive material will maintain itsaligned position upon ceasing application of the electric or magneticfield.

The one or more monomers may be polymerized using any method known tothose of skill in the art, but are preferably UV curable. Examples ofmonomers that may be used in the various embodiments of the presentinvention include, but are not limited to, urethanes, acrylates,methacrylates, silicones, epoxies, carbonates, amides, imines, lactones,aliphatic hydrocarbons, olefins, aromatics, and combinations thereof.Oligomers of any of the preceding monomers may be used, for example. Themonomers and/or oligomers are preferably well mixed with the conductivematerial and one or more moisture resistive polymers prior to thecoating step, so that the monomers and/or oligomers form a continuousmatrix upon polymerization. In some embodiments, the moisture-resistivepolymers may be present not more than, with increasing preference in theorder given, about 99, 90, 80, 70, 60, and 50 wt. %, and not less than,with increasing preference in the order given, about 45, 35, 25, 20, 15,and 10 wt. % based on the weight of the fluid.

It is preferred that the one or more moisture resistive polymers have awater vapor transmission rate (WVTR) less than or equal to 5 g/(m²*d),more preferably a WVTR less than or equal to 1 g/(m²*d). In someembodiments, the lower limit to the WVTR of the one or more moistureresistive polymers is more than or equal to 0.1 g/(m²*d), and morepreferably more than or equal to 0.01 g/(m²*d), more than or equal to0.001 g/(m²*d). Standardized tests for the determination of WVTRsinclude those approved by standard-setting bodies such as ASTMInternational (formerly known as the American Society for TestingMaterials), the International Organization for Standardization (ISO),and are quite industry-specific. ASTM has approved two test methods totrack water vapor transmission from materials: ASTM E96—Water VaporTransmission of Materials Using Gravimetric Method, and ASTM F1249—WaterVapor Transmission Rate Through Plastic Film Sheeting Using a ModulatedInfrared Sensor. Method F1249 is usually well suited to polymeric layersof sheet materials and can be used to determine whether a polymer sheetis applicable to the assemblies and methods of the present application,although method E96 may be used in instances where F1249 provesinapplicable.

Conductive materials that may be incorporated in the anisotropicconductive layer include, but are not limited to, conductive particles,for example carbon particles, nickel particles, iron particles, silverparticles, copper particles, plated polymer spheres, plated glassspheres, indium tin oxide particles, or nano-phase indium tin oxideparticles. Alternatively, conductive polymers such as polyacetylene,polyaniline, polypyrrole, poly(3,4-ethylenedioxythiophene) (PEDOT), orpolythiophene can be used. It is preferred that amount and materialsselected for the anisotropically conductive layer result in a layerhaving a conductivity that is at least about two orders of magnitudegreater in the z-axis direction, i.e. perpendicular to the plane of theanisotropically conductive layer, than the direction parallel to theplane of the layer, i.e. the x-y direction. For example, in oneembodiment of the invention, the conductivity of the anisotropicallyconductive layer in the x-y direction may be less than or equal to about10⁻¹⁰ S/cm and greater than or equal to about 10⁻⁸ S/cm in the z-axisdirection.

In a second more preferred process according to an embodiment of thepresent invention, the anisotropically conductive layer 180 may beprovided over the layer of electro-optic media 130/230 by coating thetop of the layer of electro-optic material 130/230 with a thermoplasticfluid above its melting point containing a conductive material and oneor more moisture-resistive polymers. After coating the top surface ofthe layer of electro-optic material 130/230, an electric and/or magneticfield may be applied to the thermoplastic fluid to cause the conductivematerial to align in a direction normal to the plane of the layer ofelectro-optic material 130/230. In a final step, the thermoplastic fluidis cooled during application of the electric or magnetic field, so thatthe conductive material will maintain its aligned position upon removingthe electric or magnetic field.

The second process is more preferred because it does not necessarilyrequire the presence of any potentially hazardous curable monomers, andalso the viscosity of the thermoplastic fluid may be more easilycontrolled with temperature to facilitate coating of the fluid andalignment of the conductive particles.

In yet another embodiment of the present invention, an assembly may beprovided in two steps, the first step comprising providing a front planelaminate (FPL) and the second step comprising applying an anisotropicconductive layer to the FPL.

For example, referring to FIG. 3 , an FPL 300 may comprise many of thesame layers as the assembly illustrated in FIGS. 1 and 2 . The FPL 300may include a substrate 110 having an electrode layer 120 on which alayer of an electro-optic medium 130 is applied. The FPL 300 may differ,however, in that in this first step, the electro-optic medium 130 ispreferably coated with a lamination adhesive 380 in liquid form,conveniently by slot coating, on to a release sheet 390, drying (orotherwise curing) the adhesive to form a solid layer and then laminatingthe adhesive and release sheet to the electro-optic layer 130, which mayconveniently be effected using hot roll lamination. Alternatively, butless desirably, the lamination adhesive may be applied over theelectro-optic layer 130 and there dried or otherwise cured before beingcovered with the release sheet 390. In yet another example, a thin layerof adhesive may be incorporated between the electro-optic medium 130 andthe electrode layer 120, and the release sheet 390 may be applieddirectly to the electro-optic medium 130 with no intervening adhesivelayer. The lamination adhesive is preferably an anisotropic adhesive andmay be prepared, for example, according to the procedures disclosed inU.S. Pat. No. 7,843,626.

The release sheet 390 is conveniently a 7 mil (177 μm) film; dependingupon the nature of the electro-optic medium used, it may be desirable tocoat this film with a release agent, for example a silicone. In a secondstep for forming the assembly, the release sheet 390 may be peeled orotherwise removed from the lamination adhesive 380 (as illustrated inFIG. 3 ) before an anisotropically conductive layer is applied to theFPL 300.

In another embodiment of the invention, the electro-optic medium may beprovided with a double release film, such as the “double release sheet”described in U.S. Pat. No. 7,561,324. In one form, a layer of a solidelectro-optic medium may be sandwiched between two adhesive layers(preferably anisotropic adhesives), one or both of the adhesive layersbeing covered by a release sheet. In another form, a layer of a solidelectro-optic medium may be sandwiched between two release sheets. Bothforms of the double release film may be used in a process generallysimilar to the process for assembling an electro-optic display from afront plane laminate already described. Typically, in a first laminationstep, one release sheet is removed prior laminating the electro-opticmedium to a front electrode layer to form a front sub-assembly, and thenin a second step, the second release sheet, if present, may be removedprior to application of an anisotropically conductive layer.

As previously noted, the anisotropically conductive layer may serve as aprotective layer for a display and may therefore be incorporated into anon-contact display that does not require any driving electrodes incontact with the anisotropically conductive layer to provide improvedmoisture resistant properties. Alternatively, another optional layer ofpreferably anisotropic adhesive and an optional release sheet may beapplied to the exposed surface of the anisotropically conductive layer,so that, if present, the release sheet may be later removed and theuppermost anisotropic adhesive layer contacted with driving electronics,such as a backplane, under conditions effective to cause the anisotropicadhesive layer to adhere to the driving electronics.

It will be apparent to those skilled in the art that numerous changesand modifications can be made in the specific embodiments of theinvention described above without departing from the scope of theinvention. Accordingly, the whole of the foregoing description is to beinterpreted in an illustrative and not in a limitative sense.

The entire contents of all of the aforementioned U.S. patents andpublished applications are herein incorporated by reference.

I claim:
 1. A method of forming an electro-optic assembly comprising:providing a substrate comprising an electrode layer applied to a surfaceof the substrate; applying a layer of electro-optic material to theelectrode layer on an opposing side of the electrode layer relative tothe substrate, the electro-optic material being configured to switchoptical states upon application of an electric field; coating the layerof electro-optic material with a fluid, such that the layer ofelectro-optic material is between the electrode layer and the fluid, thefluid containing a conductive material, a plurality of at least one ofmonomers and oligomers, and one or more moisture-resistive polymershaving a WVTR less than 5 g/(m2*d); applying an electric or magneticfield to the fluid to cause the conductive material to align in adirection normal to the layer of electro-optic material; and curing theplurality of monomers or oligomers during application of the electric ormagnetic field.
 2. The method of claim 1, wherein the moisture-resistivepolymer has a WVTR less than 1 g/(m²*d).
 3. The method of claim 1,wherein the moisture-resistive polymer has a WVTR more than 0.01g/(m²*d).
 4. The method of claim 1, wherein the plurality of monomersare selected from the group consisting of urethanes, acrylates,methacrylates, silicones, epoxies, carbonates, amides, imines, lactones,aliphatic hydrocarbons, olefins, aromatics, and combinations thereof. 5.The method of claim 1, wherein the moisture-resistive polymer isselected from the group consisting of polyisobutylene,styrene-isobutylene-styrene block co-polymers,poly(ethylene-co-norbornene), polyethylene, polypropylene, polyethylenenaphthalate, polyvinylidene chloride, polychlorotrifluoroethylene, andcombinations thereof.
 6. The method of claim 1, wherein themoisture-resistive polymer comprises 10 to 99 wt % of the fluid.
 7. Themethod of claim 1, wherein the electro-optic material comprises anencapsulated electrophoretic material.
 8. The method of claim 1, whereinthe cured plurality of monomers or oligomers form a planar film and theplanar film has a conductivity of at least 10⁻⁸ S/cm in a directionperpendicular to a plane of the film and less than or equal to about10⁻¹⁰ S/cm in a direction parallel to the plane of the film.
 9. A methodof forming an electro-optic assembly comprising: providing a substratecomprising an electrode layer applied to a surface of the substrate;applying a layer of electro-optic material to the electrode layer on anopposing side of the electrode layer relative to the substrate, theelectro-optic material being configured to switch optical states uponapplication of an electric field; coating the layer of electro-opticmaterial with a thermoplastic fluid, such that the layer ofelectro-optic material is between the electrode layer and thethermoplastic fluid, the thermoplastic fluid containing a conductivematerial and one or more moisture-resistive polymers having a WVTR lessthan 5 g/(m2*d); applying an electric or magnetic field to thethermoplastic fluid to cause the conductive material to align in adirection normal to the layer of electro-optic material; and cooling thethermoplastic fluid to form a solid thermoplastic during application ofthe electric or magnetic field.
 10. The method of claim 9, wherein themoisture-resistive polymer has a WVTR less than 1 g/(m²*d).
 11. Themethod of claim 9, wherein the moisture-resistive polymer has a WVTRmore than 0.01 g/(m²*d).
 12. The method of claim 9, wherein themoisture-resistive polymer is selected from the group consisting ofpolyisobutylene, styrene-isobutylene-styrene block co-polymers,poly(ethylene-co-norbornene), polyethylene, polypropylene, polyethylenenaphthalate, polyvinylidene chloride, polychlorotrifluoroethylene, andcombinations thereof.
 13. The method of claim 9, wherein electro-opticmaterial comprises a layer of encapsulated electrophoretic material. 14.The method of claim 9, wherein the solid thermoplastic forms a planarfilm and the planar film has a conductivity of at least 10⁻⁸ S/cm in adirection perpendicular to a plane of the film and less than or equal toabout 10⁻¹⁰ S/cm in a direction parallel to the plane of the film.